The terrestrial planets in the solar system are significantly drier than solids in the outer solar system.
The mass of the present Earth's ocean is only 0.02 % of the Earth's mass [1]}.
Even considering the amount of water that may have been taken into the Earth's interior,
the Earth's water content is at most 2 wt% [2]}, [3]}.
In addition, current Venus has a dry atmosphere with a water content of \(\sim \) 30 ppm [4]},
and its interior would only contain at most 10 % of the Earth's water content [5]}.
Mars is likely to contain only up to 10\(^{-4}\)  Mars' mass of water [6]}.
For Mercury, the only evidence of water is ice at the north pole, which is only 10\(^{-8}\)  Mercury's mass [7]}.
Therefore, their present water contents would be \(\lesssim 1 \)  wt%.
In contrast, bodies originating in the outer solar system, such as comets and Neptune, have a higher water content over 10 wt% [8]}, [9]}, [10]}.
